Protein Services

With more than 25 years of experience in the field, AscentGene, Inc. provides customers with Complete Protein Services (CPS), including subcloning, protein expression, protein purification and protein assays. Our protein products have been utilized for high throughput screen (HTS) assays, biomarker identification, antibody production, structural and functional studies, development of diagnostic devices, and much more.

  • Complete protein services starting from genes of interest to highly purified, active, and validated proteins
  • Protein products from different systems (E. coli, insect, mammalian)
  • Protein products from stable- or transient-transfected mammalian cells
  • Yield range of microgram to gram levels
  • Development of high expression clones for therapeutic biologics (monoclonal antibodies and proteins)
  • Protocol development for biologic production

Active and purified recombinant proteins have been widely used for the identification of biomarkers, characterization of protein functions, discovery of drug targets, and many other applications. Each protein has unique characteristics such as amino acid composition, size, and functional activity. Therefore, unlike that of DNA, each step of protein expression and purification is an art of technology that requires special handling, thorough knowledge of protein function, and experience and expertise in molecular biology, cell biology, and biochemistry.

Our Complete Protein Services
Subcloning

  • Purchase commercially available cDNA clone(s) from our partners or synthesize new genes on demand.
  • Help customer choose the proper expression vector depending on protein’s size, solubility, cell localization, functionality, post-translational modification, and purpose of project.
  • Design expression constructs with proper tag sequences (6His, Flag, HA, GST, MBP, Myc, GFP, Biotin, etc.).
  • Clone the gene of interest (GOI) into the vector.
  • Sequencing analysis to confirm GOI.

Protein Expression

  • E. coli system: Expression of a protein in E. coli cells is the most convenient and economical method to obtain a large amount of a protein. Approximately 60-70% of human proteins can be expressed and be functionally active from E. coli. However, E. coli cells lack many enzymes for post-translational modifications, such as phosphorylation, glycosylation, and acetylation. Modifications by these enzymes are essential for certain types of proteins, including cytokines, nuclear hormone receptors, protein kinases, and other regulatory proteins. Turnaround time is 1-2 weeks.
  • Baculovirus system: Expressing protein in a baculovirus system is the primary choice if post-translational modification is essential for the activity of the protein of interest. More than 95% of human proteins can be expressed and function properly in baculovirus. Three different host cell lines are currently used, including Sf9, Sf21, and HighFive cells. Turnaround time is 3-6 weeks.
  • Mammalian system: The mammalian system has certain advantages for proteins with solubility and post-translational modification problems in other expression systems. Because many mammalian cell lines are available at AscentGene, scientists have the option to study specific gene function in a specific cell line. However, expression in mammalian systems requires longer turnaround time and carries a higher cost. We provide services for protein expression in a variety of mammalian cells, including HeLa, HEK293, CHO, NIH3T3, SH-SY5Y, MCF7, MDA231, and MDA468. Development of stable cell lines or transient transfection is achievable for most mammalian cell lines. Turnaround time is 4-12 weeks.

Protein purification

  • Depending on the type, size, solubility, tag sequence, expression system, quantity, and quality of the protein requested, we combine conventional and FPLC technologies, including affinity, anion/cation exchange or hydrophobic interaction chromatography and gel filtration, to guarantee the final protein product with >90% homogeneity. Turnaround time is 1-3 weeks.

Protein identification

  • In addition to the services for purification of over-expressed proteins derived from exogenously induced genes, we purify endogenous proteins from mammalian sources (cell lines, tissues, etc.) for protein identification purposes. Turnaround time is 1-4 weeks.

Contact Us for More Information
If you would like a price quote or advice on your protein-related project, please contact us and one of our protein experts will be happy to assist you.